- Quest Giver: Armand Christophe in the Waterfront District
- Next Quest: Untaxing the Poor and Independent Thievery
- Reward: Entry into the Thieves Guild
To actually join the Thieves Guild you must be the one who wins this challenge against Amusei and Methredhel. You are tasked with finding the book "Amantius Allectus'" diary. Speak with Armand in the Garden of Dareloth to start this quest. The first to steal the diary and return it to Armand gets entry into the Thieves Guild.
 A Thief's Diary
The first way to obtain the diary is to follow Methredhel into the Imperial City, then pay a beggar 5 coins to tip you off on where to find the diary. You find out his house is in the Temple District, make your way there and into the house. Methredhel may be here but hasn't found the book, so be faster and run straight for the desk, grab the diary and wait until another meeting in the Garden of Dareloth.
 Not Outta the Game Yet
If Methredhel beats you to the diary, there's still hope! You will know she has beaten you by a quest message, read it, you are now informed that the rules stated you couldn't kill your fellow thieves but you can steal from them. Make your way to Methredhel's house, which is in front of the Garden of Dareloth. Make your way inside and open the chest and steal the diary from her, but beware of her roomates, you will have to pay a fine if they catch you. Its best to steal the diary around 5pm since no-one will be in the house at that time, just make sure your sneaking when you pick the locks or you'll still have to pay that fine. After you have the diary, return to Armand and give it to him, your now apart of the Thieves Guild.
 Last Chance
If you fail to return the diary to Armand there is one last thing you can do. Armand instructs you to steal a sword from The Fighting Chance, Amusei is no longer in ties with the guild because hes a free lance thief, not fit for the guild. This is a quest for you only, not a race, so you must not fail! The sword is in The Fighting Chance's second floor in a chest guarded by a dog, either kill the dog, charm it or sneak past it to retrieve the sword. Once you have the sword return to Armand and enjoy your decent into the Thieves Guild.
- Killing anyone but the dog in either of these quest equals dismissal from the Thieves Guild.
- Its possible to steal the diary at the last second before Methredhel meets with Armand, pickpocket her to retrieve the diary.